Laundry dryer

ABSTRACT

A dual-zone clothes dryer in which a smaller drum is disposable within the main rotatable drum, with the smaller drum in such driven engagement with the main drum that it is rotated at a speed higher than that of the main drum, and suitable to achieve tumbling of clothes within the smaller drum.

[451 Oct. 10, 1972 United States Patent Hubbard [56] References CitedUNITED STATES PATENTS [54] LAUNDRY DRYER [72] Inventor:

1,005,342 10/1911 Simpson ....................259/57 Philadelphia, Pa.

Primary Examiner-Carroll B. Dority, Jr. Attomey-Carl H. Synnestvedt [22]Filed: Dec. 24, 1970 [57] ABSTRACT A dual-zone clothes dryer in which asmaller drum is [21] Appl. No.: 101,308

[52] Us. CL 34/128 34/133 259/57 disposable within the main rotatabledrum, with the [51] Int Cl F26b 11/02 smaller drum in such drivenengagement with the I main drum that is rotated ataspeed higher thanthat [58] Field of Search..................34/128, 68/4, 259/57 of themain drum and suitable to achieve tumbling of clothes within the smallerdrum.

7 Claims, 5 Drawing Figures LAUNDRY DRYER BACKGROUND OF THE INVENTIONThis invention is concerned with household laundry apparatus andespecially with improvements in laundry dryers of the kind having aclothes-containing drum rotatable about a horizontal axis. In the use ofdryers of this kind a clothes load may contain a variety of fabricswhich require different conditions for optimum drying. For exampledifferent drying times and temperatures are desirable for fabrics ofdifferent types, and a degree of tumble agitation which is optimum forone type of fabric may not be the best for others. Frequently this isthe case with more delicate fabrics. The result has been impairment ofdrying efficiency, particularly if a small load of delicate fabrics isto be dried in a large drum.

SUMMARY OF THE INVENTION It is my objective to provide a dual-zoneclothes dryer which is not subject to the mentioned deficiencies.Broadly, this objective is achieved by utilizing the available capacityof the machine in such a way as to facilitate simultaneous drying ofdifferent types of clothing in separate drying zones. In achievement ofthis objective I utilize a drying basket or drum of smaller size, whichmay be contained within the larger drum, and provide for subjectingclothes loads within each drum to the drying action of air circulatingwithin the machine. Since the air is introduced first into the largerdrum and thereafter flows through the smaller drum, the air in thesmaller drum is cooler, ensuring more gentle drying action therein.Optimum drying time for special fabrics is readily achievable, since thesmaller drum may be removed from the machine at any time in the cycle.

' It is also an object of the invention to provide a dualzone dryingmachine operable by a single, very simple, motor drive.

The apparatus of the invention is featured by the ease with which thesmaller drum may be loaded and installed within the larger and by thefact that provision of the two drums requires no major changes in drivemeans, controls or heating circuits.

In summary, this invention provides a dryer construction having a smalldrum within which delicate fabrics may be dried, and which drum mayreadily be associated with or detached from the machine to meet variousdrying requirements. In the preferred embodiment, the invention isfeatured by the fact that, while each drum is driven at a speed suitableto promote tumbling of the clothes therein, the smaller drum derives itsmovement wholly from the larger drum.

BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawings:

FIG. 1 is a perspective illustration of a horizontalaxis laundry dryerembodying the invention;

FIG. 2 is a side sectional-elevational view showing portions of thedryer of FIG. 1 on a larger scale;

FIG. 3 is a perspective illustration of the smaller drying drum showndisassociated from the drying machine;

FIG. 4 is an exploded view illustrating features of construction of thesmaller drum and showing the manner in which it may be removablyassociated with the door of the dryer cabinet; and

FIG. 5 is a front elevational view of the two drums used in the machine,showing the drums disassociated from the dryer and illustrating thepreferred manner of driving the smaller drum.

DESCRIPTION OF THE PREFERRED EMBODIMENT Making initial reference toFIGS. 1 and 2, the illustrated laundry dryer 10 comprises a generallyrectangular cabinet 11 provided with a first, larger, open-endreceptacle or drum 12 which ismounted within the cabinet through theagency of suitable bearing means 13-14 (FIG. 2). The open end of thisdrum confronts an aperture 15 provided in the forward portion of thecabinet, as is seen in FIG. 1. Suitable door structure, for example theswinging door shown at 16, is mounted on the cabinet for movementsbetween a closed position (FIG. 2), in which it confronts the open endof the drum 12, and an open position in which access may be had to saiddrum. It will be understood that a suitable latch (not shown) would beprovided to hold the door 16 in closed position.

Preferably the drum 12 is of cylindrical shape and its periphery isformed of imperforate sheet steel. Baffles 17 provide for tumbling ofthe clothes within the drum l2. Resistive heater means, showndiagrammatically at 18 in FIG. 2, is provided to heat the air whichdries the clothes and it will be understood that the apparatus wouldfurther include motor means (not shown) for rotating the drum, forexample, through the agency of a belt 19 which surrounds the drum. Airpropelling means, shown diagrammatically as a fan identified at F, isprovided for moving the air upwardly past the heater l8, thence throughthe perforated rear wall 20 of the drum and into contact with clothescontained therein. As thus far described the main drum and driveapparatus is conventional.

As shown by arrows designating air flow in FIG. 2, the circulating airflows toward the forward part of the drum l2 and, when the smaller drumto which detailed reference will be madehereinafter is not in place,exits directly through the open end of drum 12 and through perforationsprovided in the rear wall 21 of cabinet door 16. As shown by the arrows,the air completes its circulatory flow by passing downwardly throughlint collecting means shown at 22 and thence to a suitable exit (notshown).

In particular accordance with this invention, the dryer is provided witha second receptacle or drum 23, smaller than the first drum. This seconddrum, which may conveniently be fabricated of molded plastic material tominimize the weight thereof, is provided with a fixed end wall 24 whichis perforated, and with a removable perforated cap or wall 25 which isflanged, as shown at 26, (see particularly FIG. 4) releasably to retainthe cap on the drum. The removable cap 25 provides access to drum 23, inthe manner shown in FIG. 4, and serves also to retain a lint filter 27.This filter is supported between the removable cap wall 25 and a flangedportion 28 of smaller drum 23. The smaller drum is provided with baffles29 which may be conventional in nature.

Drum 23 is removably and rotatably supported upon the door 16 and, forthis purpose, the end wall 24 of drum 23 is provided with anextemalIy-splined shaft 30 which is receivable within an internallysplined hollow shaft or socket structure 31 mounted in the door 16through the agency of a journal 32 and a set of bearings 33. The endwall 24 of the smaller drum is provided with a flange 240 which seatsagainst the front of the cabinet, as shown at 24b in FIG. 1, to preventinadvertent dislodgement of the drum 23 when it is in use. To providefor driving the smaller drum at a desired speed, different than that ofthe larger drum, the journal 32 is so located and secured within thedoor that the socket structure 31 defines a rotational axis A for thesmaller drum which is eccentric with respect to the axis B of the largerdrum (FIG. 2).

As will now be understood, smaller drum 23 may readily be associatedwith and disassociated from the door and access may be had to itsinterior through the cap structure 25, 26. If desired, means (not shown)may be provided to cover the internally splined socket structure 31 whenthe smaller drum is not in use.

When the smaller drum is in use, circulating air flows first through thelarger drum and thereafter through the smaller drum, exiting throughperforated drum wall 24 into and through the door, as shown by thearrows in FIG. 2. As noted above it is of advantage, in drying certainfabrics, that the air is at a lower temperature by the time it reachesthe smaller drum.

Preferably the wall 21 of the door is also perforated, as shown at 21ain FIG. 1, in a lower region which is not covered by the smaller drumwhen the latter is in place. This permits some outflow of air directlyfrom the larger drum, even if the smaller drum is in use.

While the invention is not limited to use of drums of any particularsize, the larger drum 12 may, for example, have a diameter of about 29inches and its forward access opening 15a may have a diameter of about18 inches. As shown below, when a larger drum having these dimensions isused, the smaller drum 23 will have a diameter of about 12 inches. Adrum of this size is readily insertable within the larger drum when thedoor 16 is swung from the position shown in FIG. 1 to the position shownin FIG. 2.

As will be understood, the larger drum is driven through the belt 19 anddrive motor (not shown) at a speed suitable to cause tumbling of fabricscontained therein, for example about 48 rpm, for a 29 inch drum. Thisspeed, and use of appropriate baffles, provides a satisfactory tumblepattern.

In the broader aspect of the invention, any convenient means may beemployed for driving the smaller drum at the proper tumble speeds.However, it is a feature of the preferred embodiment of my inventionthat a drive connection between the drums is established automaticallywhen the second drum is positioned within the first, and it is highlyadvantageous that the smaller drum be driven by the larger drum. By useof such an arrangement it is possible to achieve speeds which areoptimum for the achievement of tumbling in the two drums, withoutimposing any unusual requirements as to power or drive mechanism for thelarger drum.

Frictional drive means may be interposed between the two drums, with theresultant advantage of low noise, but I prefer to use an internal gearsecured to the larger drum l2 and extending around its opening 15a. Thisgear may comprise an internally toothed belt of suitable material, forexample plastic material. An external gear is provided also preferablyas a belt and extends about the periphery of the smaller drum, adjacentthe region in which it is supported by the door.

The gearing arrangement appears to best advantage in FIGS. 1 and 5. Theexternal belt gear 34 is secured in any suitable fashion, about theperiphery of smaller drum 23, while the internal belt gear 35 extendsand is secured by any convenient means around the access opening 15a ofthe larger drum and lies generally in the plane of said access opening,which is in registry with the opening in the forward wall of thecabinet. Although the gear teeth provided on the two belts need not beprecisely formed, preferably they are of approximately involute shape.As the door 16, carrying the smaller drum, is swung toward theclosedposition the external teeth of gear ring 34 are brought into engagementwith the internal teeth of ring 35. The two drums are shown in FIG. 5disassociated from the cabinet, and a portion of the forward wall ofdrum 12, which wall defines the drum opening 15a, is shown broken awayto illustrate the engagement between the gears 34 and 35. If necessarythe ends of the teeth may be bevelled to accommodate engagement anddisengagement thereof.

As mentioned above, a drum 29 inches in diameter must be rotated atabout 48 rpm to achieve a value of centrifugal force within the drumwhich is slightly less than the force of gravity. As is known in thisart, a value for centrifugal force slightly less than gravity isrequired for proper tumbling in a horizontal axis clothes dryer. In anyparticular design the smaller drum must be of a diameter such that itwill pass freely into the larger drum. Further, if it is to carry anexternal gear or friction means, the diameter of the smaller drum alsomust be so chosen that it rotates at a speed which results in a value ofcentrifugal force within said smaller drum which is slightly less thanthe force of gravity. As shown below, a smaller drum 12 inches indiameter meets these conditions.

The speed of rotation of the larger drum, multiplied by the ratio of thediameters of the two gears, equals the speed of rotation of the smallerdrum. For simplicity in calculating the rotational speeds of the drums,the value given above for the diameter of the smaller drum (12 inches)should be understood as comprising the diameter of the pitch circle ofits external gear. Similarly, the diameter of the opening 15a 18 inches)should be understood as being the diameter of the pitch circle of theinternal gear carried by the larger drum.

Since, in the particular apparatus under consideration, the larger drumcarries an internal gear which is concentric therewith and is 18 inchesin diameter, and since the diameter of the external gear isapproximately equal to that of the smaller drum, the speed of rotationof the smaller drum is 48 X 18/ l 2 72 rpm. This can be shown to yield avalue for centrifugal force which is in the region of 0.9 G, and propertumbling is achieved.

I claim:

1. In apparatus for drying fabrics: a first open-end receptacle; meanssupporting said receptacle for rotation about a generally horizontalaxis; door structure movable between a closed position in which itconfronts the open end of said receptacle and an open position in whichaccess may be had to said receptacle; a second receptacle smaller thansaid first receptacle;

means removably and rotatably supporting said second receptacle uponsaid door structure in a position such that closing of said doorstructure causes said second receptacle to be moved into said firstreceptacle and to occupy a position therein in which it may be rotatedabout a generally horizontal axis; means for driving said firstreceptacle at a speed suitable to cause tumbling of fabrics containedtherein; and means for establishing a driving connection between saidreceptacles when said second receptacle is positioned within said firstreceptacle, the driving connection being such that said first receptacledrives said second receptacle at a speed higher than that of said firstreceptacle and suitable to cause tumbling of fabrics contained in saidsmaller second receptacle.

2. Apparatus in accordance with claim 1, in which said receptacles areperforated and there is included means for passing drying air into saidfirst receptacle and for thereafter passing said air into and throughsaid second receptacle.

3. Apparatus in accordance with claim 1, and further characterized inthat said door structure is provided with journal means for rotatablyand removably supporting said second receptacle.

4. A clothes dryer comprising: a cabinet; an openend drum rotatablysupported by said cabinet, said cabinet having an opening in registrywith the open end of said drum; a door normally closing said opening insaid cabinet and movable to a position in which access may be had to theinterior of said drum; and a second smaller drum carried by said doorand normally disposed within the larger drum; the construction andarrangement being such that clothes contained within each of said drumsare subjected to drying air circulating through the cabinet, andprovision is made to rotate said drums simultaneously each at a speedsuitable to produce tumbling of clothes therein.

5. In a dual-zone laundry dryer: a main drum rotatable about asubstantially horizontal axis; means for driving said main drum at aspeed suitable to tumble fabrics therein; a smaller drum disposed withinthe main drum and rotatable about a substantially horizontal axiseccentric with respect to the axis about which said main drum isrotatable; and means establishing a driving connection between said maindrum and said smaller drum, said driving connection being such that saidsmaller drum is driven by said main drum at a speed higher than that ofsaid main drum and suitable to tumble fabrics in said smaller drum.

6. Apparatus in accordance with claim 5, and further characterized inthat said driving connection comprises: an internal gear carried by andconcentric with the axis of rotation of said main drum; and an externalgear carried by and concentric with the axis of rotation of said smallerdrum and in driven engagement with said internal gear.

7. Apparatus in accordance with claim 6, and in which said main drum hasa forward access opening, said internal gear surrounds said opening, andsaid external gear surrounds and is carried by the peripheral wall ofsaid smaller drum.

1. In apparatus for drying fabrics: a first open-end receptacle; meanssupporting said receptacle for rotation about a generally horizontalaxis; door structure movable between a closed position in which itconfronts the open end of said receptacle and an open position in whichaccess may be had to said receptacle; a second receptacle smaller thansaid first receptacle; means removably and rotatably supporting saidsecond receptacle upon said door structure in a position such thatclosing of said door structure causes said second receptacle to be movedinto said first receptacle and to occupy a position therein in which itmay be rotated about a generally horizontal axis; means for driving saidfirst receptacle at a speed suitable to cause tumbling of fabricscontained therein; and means for establishing a driving connectionbetween said receptacles when said second receptacle is positionedwithin said first receptacle, the driving connection being such thatsaid first receptacle drives said second receptacle at a speed higherthan that of said first receptacle and suitable to cause tumbling offabrics contained in said smaller second receptacle.
 2. Apparatus inaccordance with claim 1, in which said receptacles are perforated andthere is included means for passing drying air into said firstreceptacle and for thereafter passing said air into and through saidsecond receptacle.
 3. Apparatus in accordance with claim 1, and furthercharacterized in that said door structure is provided with journal meansfor rotatably and removably supporting said second receptacle.
 4. Aclothes dryer comprising: a cabinet; an open-end drum rotatablysupported by said cabinet, said cabinet having an opening in registrywith the open end of said drum; a door normally closing said opening insaid cabinet and movable to a position in which access may be had to theinterior of said drum; and a second smaller drum carried by said doorand normally disposed within the larger drum; the construction andarrangement being such that clothes contained within each of said drumsare subjected to drying air circulating through the cabinet, andprovision is made to rotate said drums simultaneously each at a speedsuitable to produce tumbling of clotheS therein.
 5. In a dual-zonelaundry dryer: a main drum rotatable about a substantially horizontalaxis; means for driving said main drum at a speed suitable to tumblefabrics therein; a smaller drum disposed within the main drum androtatable about a substantially horizontal axis eccentric with respectto the axis about which said main drum is rotatable; and meansestablishing a driving connection between said main drum and saidsmaller drum, said driving connection being such that said smaller drumis driven by said main drum at a speed higher than that of said maindrum and suitable to tumble fabrics in said smaller drum.
 6. Apparatusin accordance with claim 5, and further characterized in that saiddriving connection comprises: an internal gear carried by and concentricwith the axis of rotation of said main drum; and an external gearcarried by and concentric with the axis of rotation of said smaller drumand in driven engagement with said internal gear.
 7. Apparatus inaccordance with claim 6, and in which said main drum has a forwardaccess opening, said internal gear surrounds said opening, and saidexternal gear surrounds and is carried by the peripheral wall of saidsmaller drum.